It is sweetened with 30 g stevia/erythritol — swap the sugar for that if you prefer. Commenters on the reel were split on bitterness from the raw peel; one suggested simmering the orange first to soften it. Gluten-free conversion by Yael: a GF 1:1-style flour blend (no gum in the blend) with baking powder and salt in place of self-raising flour, plus a 20-minute batter rest. Not yet test-baked. Equipment note from our test bake: a standard blender may struggle with the whole orange — a food processor finishes the job well.